The reference evapotranspiration (ETo) is an important agrometeorological parameter which has been used in a number of applications. In present study daily ETo was determined for seven districts of Marathwada region having long period (29-35 years) weather data by Hargreaves method. The Kc values for kharif sorghum, maize and pearlmillet as given in FAO-56 paper was used to calculate the daily crop water requirement (ETc). The results revealed that, ETo reaches to its peak value during 28th April to 18th May at all the districts of marathwada region. Among the districts, Parbhani had highest ETo and Aurangabad had lowest ETo followed by Nanded, Latur, Osmanabad, Beed and Jalna. The mean water requirement (ETc) of kharif sorghum during initial stage was found to be lower (1.83 to 2.0 mm day-1 ) and it increased during developmental stage (3.34 to 3.70 mm day-1 ) and during mid season stage (4.70 to 5.10 mm day-1 ) and decreased during late-season stage (2.91 to 3.13 mm day-1 ). The total water requirement across the districts varies between Parbhani (436.04 mm) to Aurangabad (399.42 mm). The mean water requirement of kharif maize during initial stage (1.59 to 1.74 mm day-1 ), during developmental stage (2.77 to 3.08 mm day-1 ), during mid season stage (5.07 to 5.54 mm day-1 ) and during late season stage it decreases (1.55 to 1.67 mm day-1 ). The total water requirement of kharif maize varies between Parbhani (373.13 mm) and Aurangabad (340.74 mm).
Trang 1Original Research Article https://doi.org/10.20546/ijcmas.2019.802.284
Estimation of Reference Evapotranspiration (ETo) and Crop Water
Requirement of Major Kharif Cereals of Marathwada Region, Maharashtra
S.V Phad*, K.K Dakhore and R.S Sayyad
Department of Agricultural Meteorology, Vasantrao Naik Marathwada Krishi Vidyapeeth,
Parbhani 431 402, Maharashtra, India
*Corresponding author
A B S T R A C T
Introduction
Water is one of the most essential natural
resource which plays a vital role in
maintaining biodiversity, our health, social
welfare and our economic development
(Donald, 1968)
In planning and management of available water resources for agricultural sector, the defining strategies become a national and global priority The reference evapotranspiration (ETo) is defined as the loss of water to the atmosphere by evaporation and transpiration from an
International Journal of Current Microbiology and Applied Sciences
ISSN: 2319-7706 Volume 8 Number 02 (2019)
Journal homepage: http://www.ijcmas.com
The reference evapotranspiration (ETo) is an important agrometeorological parameter which has been used in a number of applications In present study daily ETo was determined for seven districts of Marathwada region having long period (29-35 years)
weather data by Hargreaves method The Kc values for kharif sorghum, maize and
pearlmillet as given in FAO-56 paper was used to calculate the daily crop water requirement (ETc) The results revealed that, ETo reaches to its peak value during 28th April to 18th May at all the districts of marathwada region Among the districts, Parbhani had highest ETo and Aurangabad had lowest ETo followed by Nanded, Latur, Osmanabad,
Beed and Jalna The mean water requirement (ETc) of kharif sorghum during initial stage
was found to be lower (1.83 to 2.0 mm day-1) and it increased during developmental stage (3.34 to 3.70 mm day-1) and during mid season stage (4.70 to 5.10 mm day-1) and decreased during late-season stage (2.91 to 3.13 mm day-1) The total water requirement across the districts varies between Parbhani (436.04 mm) to Aurangabad (399.42 mm)
The mean water requirement of kharif maize during initial stage (1.59 to 1.74 mm day-1), during developmental stage (2.77 to 3.08 mm day-1), during mid season stage (5.07 to 5.54
mm day-1) and during late season stage it decreases (1.55 to 1.67 mm day-1) The total
water requirement of kharif maize varies between Parbhani (373.13 mm) and Aurangabad (340.74 mm) The mean water requirement of kharif pearlmillet during initial stage (1.85
to 2.03 mm day-1), during developmental stage (2.82 to 3.13 mm day-1), during mid season stage (4.21 to 4.64 mm day-1) and during late season stage it decreases (1.29 to 1.38 mm day-1) The total water requirement of kharif pearlmillet varies between Parbhani (291.69
mm) and Aurangabad (265.02 mm)
K e y w o r d s
Evapotranspiration
(ETo) and Crop
Water,
Kharif Cereals
Accepted:
18 January 2019
Available Online:
10 February 2019
Article Info
Trang 2extended surface of 8-12 cm tall green grass
cover, usually a well-watered, actively
growing and completely shading the ground
The prediction of evapotranspiration is based
on meteorological variables like temperature,
humidity, sunshine hour, wind speed By
applying a crop coefficient (Kc) values, this
ETo can be used to estimate the crop
evapotranspiration (ETc), (Doorenbos and
Pruitt, 1975) The adoption of exact or correct
amount of water and correct timing of
application is very essential for scheduling
irrigations to meet the crop’s water use
demands and for optimum crop production
Estimation of crop water requirements (ETc)
is one of the main components used in
irrigation planning, design and operation
(Rowshon et al., 2013) Jensen et al., (1990),
provided detailed reviews of the methods
commonly used to determine
evapotranspiration and estimated crop water
requirements
In this paper attempt has been made to
determine reference evapotranspiration
(ETo)) and crop water requirement (ETc) of
major kharif cereals (Sorghum, Maize and
Pearlmillet) using long period weather data
(1982-2017) of different districts of
Marathwada region
Materials and Methods
Location of study area
The Marathwada region of Maharashtra states
comprises of eight districts total area of 64818
sq km geographically lies between 17o35' to
20o 40' latitude and 74o 40' to 78o10'
longitude The altitude ranges between 300
and 900 meter above mean sea level (MSL)
The present study is conformed to
Marathwada region comprising of 8 districts
with total geographical area is 64.5 lakh ha
with 57.0 lakh ha land suitable for agriculture
Table 1 shows detailed information of
different districts of Marathwada Region
Collection and processing of meteorological data
Daily weather data of maximum and minimum temperature of selected districts for
at least 29 to 35 years period was collected from India Meteorological Department (IMD), Pune The collected data of each district were used to work out mean of each parameter of each district and then those daily mean data used to calculate reference evapotranspiration (ETo) The daily crop water requirement (ETc) was determined by multiplying daily ETo of each districts with
Kc, determined for each crop Thus daily ETc computed were summed for different growth stages of crop and total seasonal crop water was determined
Estimation of reference evapotranspiration (ETo)
Hargreaves method
Hargreaves developed a method in 1985 to estimate evapotranspiration is an empirical relation based on air temperature and radiation (Basanagouda, 2016) The Hargreaves method is given by:
ETo = 0.0023 RA Td0.5 (Tm + 17.8)
Where, ETo is reference evapotranspiration (mm day-1)
RA is extra-terrestrial radiation (mm day-1)
Td is difference between maximum and minimum temperature (oC)
Tm is mean temperature (oC)
Crop evapotranspiration/crop water requirement (ETc)
The amount of water required to compensate the evapotranspiration loss from the cropped field is defined as crop water requirement The crop evapotranspiration differs distinctly
Trang 3from the reference evapotranspiration (ETo)
as the ground cover, canopy properties and
aerodynamic resistance of the crop are
different from grass
ETc = Kc ETo
Where,
ETc = crop evapotranspiration/Crop water
requirement, (mm day-1),
ETo = reference evapotranspiration, (mm day
-1
),
Kc = crop coefficient
The total duration of these crops were divided
into four growth stages initial, developmental,
mid-season and late-season The initial stage
refers to the germination and early growth
stage when the soil surface is not or is hardly
covered by the crop The crop development
stage is the stage from the end of the initial
stage to attainment of effective full ground
cover (groundcover 70-80%) The mid-season
stage is the stage from attainment of effective
full groundcover to the start of maturity, as
indicated by discolouring of leaves or falling
of leaves The late season stage runs from the
start of maturity to harvest or full senescence
Table 2 shows FAO crop coefficients (Kc)
values and Table 3 shows Crops, their season
and length of crop growth stages for various
Sowing periods (days)
Results and Discussion
Reference evapotranspiration (ETo) for
Marathwada region
Variation of ETo on daily basis
The daily variation of ETo for seven districts
of marathwada region observed that there is
large fluctuation in daily ETo at different
districts of marathwada region Although the
daily ETo increases continuously from
January and reaches to its maximum during
May, but there is quite differences among the districts The ETo reaches to its peak value during 28th April to 18th May at all the districts of marathwada region During June ETo decreases sharply and remains low during July and August and with slight increase during month of September, it decreases afterwards (Fig 1) The Hargreaves method shows, range of ETo was found highest at Parbhani 3.81 mm day-1 (26th Dec)
to 7.84 mm day-1 (30th April) with mean annual value of 5.39 mm day-1 and lowest at Aurangabad 3.67 mm day-1 (28th and 29th Dec) to 7.28 mm day-1 (27th and 28th April), with mean annual value of 5.04 mm day-1 as compared to rest of the districts (Table 4) (Mehta R (2015)
Crop Evapotranspiration/Crop Water Requirement (ETc)
ETc of Kharif Sorghum
The daily ETc of sorghum determined for seven districts along with the mean values by Hargreaves method revealed that, During initial stage of crop, total water requirement
in region varies between 36.59 to 40.09 mm with mean water requirement varies between 1.83 to 2.0 mm day-1, During developmental stage of crop, total water requirement in region varies between 116.75 to 129.65 mm with mean water requirement varies between 3.34 to 3.70 mm day-1, During the mid stage
of crop, total water requirement in region varies between 187.95 to 203.84 mm with mean water requirement varies between 4.70
to 5.10 mm day-1, During the late-season stage of crop, total water requirement in region varies between 55.23 to 59.51 mm with mean water requirement varies between 2.91 to 3.13 mm day-1 It is found from above discussion that the variation in ETc is more at developmental and mid-season stages as compared to initial and maturity stages of the sorghum crop across the districts Among the
Trang 4different districts, the highest ETc is observed
at Parbhani (436.04 mm) while the lowest
value is at Aurangabad (399.42 mm) followed
Jalna (411.27 mm), Nanded (430.78 mm),
Osmanabad (423.73 mm), Latur (417.21 mm),
Beed (418.02 mm) (Table 5) (Chavan M.L.,
2009)
ETc of Kharif maize
The daily ETc of maize determined for seven
districts along with the mean values by
Hargreaves method revealed that During
initial stage of crop, total water requirement
in region varies between 23.84 to 26.08 mm
with mean water requirement varies between
1.59 to 1.74 mm day-1, During developmental
stage of crop, total water requirement in
region varies between 82.98 to 92.28 mm
with mean water requirement varies between
2.77 to 3.08 mm day-1, During the mid stage
of crop, total water requirement in region varies between 202.90 to 221.79 mm with mean water requirement varies between 5.07
to 5.54 mm day-1, During the late-season stage of crop, total water requirement in region varies between 31.03 to 33.40 mm with mean water requirement varies between 1.55 to 1.67 mm day-1 It is found from above discussion that the variation in ETc is more at developmental and mid-season stages as compared to initial and maturity stages of the sorghum crop across the districts Among the different districts, the highest ETc is observed
at Parbhani (373.13 mm) while the lowest value is at Aurangabad (340.74 mm) followed Jalna (351.94 mm), Nanded (370.32 mm), Osmanabad (364.22 mm), Latur (357.79 mm), Beed (360.62 mm) (Table 6) (Chavan, 2009)
Table.1 Detailed information of different districts of Marathwada Region
Districts Latitude Longitude Altitude(m) Data
Availability
Table.2 FAO crop coefficients (Kc) for non stressed, well-managed crops in semi-arid climates
Trang 5Table.3 Crops, their season and length of crop growth stages for various Sowing periods (days)
Sr
No
(days) Initial Developmental Mid-season Late-season Sowing Harvesting
Table.5 ETc of kharif sorghum by Hargreaves method at different districts of Marathwada region
District Initial Stage Developmental Stage Mid-Season Stage Late-Season Stage Total
Trang 6Table.6 ETc of kharif maize by Hargreaves method at different districts of Marathwada region
District Initial Stage Developmental Stage Mid-Season Stage Late-Season Stage Total
Table.7 ETc of kharif pearlmillet by Hargreaves method at different districts of Marathwada region
District Initial Stage Developmental Stage Mid-Season Stage Late-Season Stage Total
Trang 7Fig.1 Daily variation of ETo (mm day-1) by Hargreaves method at different districts of
Marathwada region
ETc of Kharif Pearlmillet
The daily ETc of pearlmillet determined for
seven districts along with the mean values
by Hargreaves method revealed that, During
initial stage of crop, total water requirement
in region varies between 27.81 to 30.42 mm
with mean water requirement varies between
1.85 to 2.03 mm day-1, During
developmental stage of crop, total water
requirement in region varies between 73.21
to 81.32 mm with mean water requirement
varies between 2.82 to 3.13 mm day-1,
During the mid stage of crop, total water
requirement in region varies between 147.48
to 162.47 mm with mean water requirement
varies between 4.21 to 4.64 mm day-1,
During the late-season stage of crop, total
water requirement in region varies between
19.33 to 20.76 mm with mean water
requirement varies between 1.29 to 1.38 mm
day-1 It is found from above discussion that
the variation in ETc is more at
developmental and mid-season stages as
compared to initial and maturity stages of
the sorghum crop across the districts
Among the different districts, the highest
ETc is observed at Parbhani (291.69 mm)
while the lowest value is at Aurangabad (265.02 mm) followed Jalna (273.33 mm), Nanded (289.46 mm), Osmanabad (283.16 mm), Latur (280.25 mm), Beed (282.11 mm) (Table 7) (Chavan, 2009)
It is concluded that, ETo increases continuously from January and reaches to its maximum during May then in the month of June ETo decreases sharply and remains low during July and August and with slight increase in the month of September, it
decreases afterwards In summer season
when the temperature and wind speed both are highest so the total ETo was maximum,
while in kharif season there may be wind
speed is high but temperature comparatively
lower than the summer due to rainfall
thereby less ETo Among the districts Parbhani had highest ETo and Aurangabad had lowest ETo followed by Nanded, Latur, Osmanabad, Beed and Jalna The crop water
requirement (ETc) of major kharif cereals
was found to vary not only with the crops it’s stage and duration, but also with the season as well During initial stage of the crops, the ETc was less and increased during development stage, reached to its maximum
Trang 8values during mid season and reduced
during crop maturation stages Among the
districts, crop water requirement for major
kharif cereals found highest at Parbhani and
lowest at Aurangabad followed by Nanded,
Latur, Osmanabad, Beed and Jalna
References
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How to cite this article:
Phad, S.V., K.K Dakhore and Sayyad, R.S 2019 Estimation of Reference Evapotranspiration
(ETo) and Crop Water Requirement of Major Kharif Cereals of Marathwada Region, Maharashtra Int.J.Curr.Microbiol.App.Sci 8(02): 2441-2448
doi: https://doi.org/10.20546/ijcmas.2019.802.284